The present invention relates to a brake disk for a disk brake and, in particular, for a disk brake for utility vehicles.
Disk brakes for vehicles are known, for example, as sliding-caliper disk brakes, swivelling-caliper disk brakes or fixed-caliper disk brakes. In the utility vehicle field, particularly the sliding-caliper brake has become a successful standard design, in which case the sliding caliper is displaceably disposed on a brake anchor plate rigidly fastened to the wheel axle. Sliding-caliper or swivelling-caliper disk brakes require a component—the brake anchor plate—which is fixed to the axle and which, when the brake is operated, absorbs the circumferential forces of the brake linings with the brake pads. Also, the brake anchor plate holds the caliper, which is slidably or swivellably disposed with respect to the vehicle axle.
If a fixed caliper is used instead of a sliding caliper, the brake disk may be designed as a sliding disk, which is axially displaceably disposed on the wheel axle. During brakings, it is first contacted by a brake pad and then pushed against the brake pad arranged on the opposite side of the brake disk. In this case, generally, the generating of force—that is, the brake application device—and a wear adjusting device are arranged on one side of the brake disk. As the wear increases, the brake disk is also slowly axially slid on the wheel axle in order to compensate the wear of the brake pad.
The relative movement, which the sliding disk therefore has to bridge, can be divided into a working stroke and a wear stroke.
The working stroke is carried out during each brake operation in order to overcome the release play of the brake and compensate for the elasticities of the brake pads and of the caliper during the application of force.
In contrast, the wear stroke is the wear adjusting path, which the caliper carries out over a large number of brake operations, in order to compensate for the wear on the reaction side of the brake. The wear stroke is composed of the wear of the externally situated brake pad and of the externally situated brake disk friction surface and normally amounts to 20-25 millimeters, while the above-mentioned working stroke, and thus the sliding path for overcoming the release play, amounts to only a few millimeters.
If at least one adjusting device is arranged on each side of the brake disk, for example, in each case at least one or more electric-motor-driven adjusting rotating device(s) which move(s) pressure pieces in the direction of the brake pads, the distance between the brake pad and the brake disk can be adjusted on each side of the brake disk.
In such a case, it is necessary to still implement a displaceability of the brake disk for overcoming the release play and for compensating the elastic deformation of the brake pads and of the caliper, in accordance with the above-mentioned working stroke. Correspondingly, the slide bearing needs to have a displacement path however, a correspondingly clearly shorter one.
Although the use of such an adjusting system with at least one or more adjusting devices on each axial side of the brake disk already represents a considerable improvement, as a result of the still axial displaceability of the brake disk, a sliding guide can be implemented, although to a lesser extent. Thus, the frequent operation, typical of the use of a disk brake in a utility vehicle, because of the influencing forces, permanently leads to a wear of the sliding guide by which the brake disk is guided on the hub, resulting in sluggishness which requires corresponding maintenance work.
This is naturally has its costs, which are the result of the maintenance work as well as of the necessary interruptions in the operation of the vehicle.
It is therefore an object of the present invention to further develop the brake disk of the above-mentioned type such that a longer service life can be achieved by the use of constructively simple devices.
This object is achieved by providing a brake disk for a disk brake, particularly for a disk brake of a utility vehicle, having: a) two mutually connected friction rings, between which a ventilating gap is formed; b) a device for implementing an axial mobility of the friction rings relative to the wheel hub and/or wheel axle; and c) wherein the device for implementing the axial mobility of the friction rings is designed as a linking piece arranged on the friction rings and/or connected therewith, for the fastening of the brake disk to the wheel hub and/or wheel axle, which linking piece is constructed separately from the friction rings and can be elastically deformed relative to the friction rings.
Accordingly, the device for implementing the axial mobility of the friction rings is designed as a linking piece, which is arranged at the friction rings and/or is connected with them, for fastening the brake disk at the wheel hub and/or the wheel axle. The linking piece is constructed separately from the friction rings and can be elastically deformed relative to the friction rings.
As a result of this simple construction, an elastic linkage of the brake disk to the wheel hub and/or wheel axle is created, which advantageously does not require an axial displaceability or a bearing between the brake disk and the wheel hub and/or the wheel axle.
Since, to this extent, the brake disk is firmly but not rigidly linked with the hub, the wear parts required for an axial displacement are also eliminated. This results in a considerably lower susceptibility to disturbances so that maintenance and operating costs are correspondingly lowered with respect to the state of the art.
Preferably, the one-part or multi-part linking piece has a radial dimension relative to the wheel axle and is axially elastically deformable relative to the friction rings. Particularly preferably, the linking piece can be axially elastically deformed relative to the friction rings and the wheel axle in such a manner that, as a result of the elastic deformability, an axial mobility of the friction rings relative to the wheel axle is implemented, which axial mobility corresponds to the amount of the working stroke of a disk brake.
The brake disk is, therefore, suitable for, among others, fixed-caliper brakes which have adjusting devices on each side of the brake disk because, in the case of these types of brakes, only an axial deflectability of the brake disk must be ensured that is sufficient such that the working stroke is compensated. Optionally, in a supplementary manner, a low elastic deflectability of the caliper can be combined with the elastic deflectability of the brake disk according to the invention.
According to an advantageous further development of the invention, it is provided that the linking piece is arranged between the two friction rings and is fixedly connected with these, preferably in the outer circumferential area.
In order to obtain a sufficient elasticity, the linking piece, which consists of a springy material, preferably of a spring steel, is provided with recesses by which, depending on their shape and number, a defined restoring force can be reached or adjusted.
The linking piece is connected with the friction rings only in areas, or partially, and can otherwise be moved, that is, deflected with respect to these.
Otherwise, in the case of installation conditions of the brake disk having only a small distance between the inside diameter of the brake disk and the outside diameter of the hub, the invention is suitable for achieving a sufficiently large deflecting movement of the brake disk while the restoring forces are low. On the other hand, the elastic linkage permits the transmission of high braking torques of the brake disk to the hub.
By means of the arrangement of the linking piece in the ventilating duct formed between the two friction rings, a relatively large bending length of the linking piece can be achieved, whereby the linking piece can be sufficiently dimensioned for the transmission of the braking torque and the elastic linking piece does not impair the deflection of the brake disk and thus the function of the brake. Thus, an excessive deflecting resistance could result in an unequal stressing of the two brake disk sides, and thus cause an unequal wearing of the brake.
The linking piece may have many different constructions. One possibility consists of embedding, in the case of a composition casting method for producing the brake disk, the ring-shaped linking piece in a casting core, which is used for generating the ventilating duct of the brake disk. The casting core is constructed such that the casting material penetrates through exterior openings of the linking piece, so that, here, the linking piece is fastened to the two cast and mutually connected friction rings.
Furthermore, the linking piece consisting of a spring plate may be placed between the two friction rings, specifically such that, viewed in the cross-sectional direction, it is arranged approximately in the center of the ventilating duct, thus at the same distance from the respectively adjacent friction rings.
In this case, the linking piece is held in a radially secured manner in the linking areas in the exterior circumferential area between the two friction rings, these being mutually connected by riveting, screwing, welding or another connecting method.
For increasing the elasticity in the pressure direction of the brake disk, the linking piece may also be constructed as a lamellar body and consist of several thin, mutually stacked, individual metal sheets.
It is also contemplated for the linking piece to be produced of a plurality of individual ring segments which, in their respective common abutting areas, are provided with mutually corresponding profiles, whereby a simplification of the mounting and an optimized circumferential force transmission becomes possible.
Instead of many ring segments, which together result in a closed ring, the linking piece may also consist of a plurality of individual elements which each, on one side, are fastened in the circumferential area on the brake disk in the ventilating gap and, on the other side, are connected with the hub. In this case, the individual elements may be constructed and arranged in the manner of spokes and each consist of a spring steel which has a flat or round cross-section.
A brake disk for a disk brake, particularly for utility vehicles, is created which consists of two mutually spaced friction rings which thereby form a ventilating gap and are connected with one another, and which is non-rotatably connected to a wheel hub and/or wheel axle such that it is fastened by the use of a separate, radially extending linking piece to the hub so that it can be elastically deflected in the axial direction of the hub.
Additional advantageous further developments of the invention are described and claimed herein.